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Timing of Prenatal Tests

From ob-gyn-l:

When should the first prenatal testing be done? Do most people get an OB profile (ABO, Rh, antibody screen, CBC, RPR, HBsAg, +/- HIV, Rubella), pap smear, and cultures on the first OB visit or do you wait until after the patient returns for the second visit?

Can you think of potential adverse maternal-fetal or medicolegal consequences from not performing the tests at the first visit? Is there a "standard of care"?

I am in solo (soon to be a group) practice in middle class to upper middle class suburban Atlanta. Most women come in for a

first visit by 10 weeks. Most are low risk, so let's only talk about them.

1. I do not do the prenatal panel/profile before I have seen or heard heart tones; it saves money if spont Ab/missed Ab. If the have a missed, then I get the Rh from the chart, or, if needed, order one with preop D and C blood.
2. At the first visit, I introduce the AFP-3 or whatever test. When they return, and if they want the AFP, all blood waits until 16 to 18 weeks; if they need early GDM screening, I do that, too.

I am unable to find a reason why I need the prenatal panel prior to 16 weeks in someone who wants an AFP. It saves a stick for them, and they appreciate it. It saves nurse time.

Exceptions:

• Those going for Amnio/CVS
• First trimester bleeders who Rh is unknown in whom you might give RhoGAM if negative.

Pap and cultures (don't do them in my squeaky clean folks) at the first visit with pelvic.

We used to do the same thing, i.e. wait until 16 weeks to do all the prenatal labs, until we had a patient, who totally unexpectedly, came up HIV positive on initial screen. By the time the Western Blot, PCR, counseling, etc, were done, she was well beyond 20 weeks, and had a very difficult time emotionally with her decision to terminate the pregnancy (this was several years ago, before the current AZT data).

Without making value judgments, this was the last patient I would have expected in my practice to be HIV positive: less than 5 sequential monogamous relationships in college, no drugs, transfusions, etc., husband HIV negative (still is).

She and her husband asked why we weren't able to find this out sooner. I was honest with them about why we tried to save a stick and do all the labs at 16 weeks, but in all honesty, it rang hollow.

Since then, we draw prenatals at the first visit.

There are times when a patient will present with a newly diagnosed pregnancy, but will not be seeing us for prenatal care. So we are a little cautious about ordering all lab work at the drop of a hat. We also have a large group of uninsured people who we've seen in the past, but have never paid us anything. They are ultimately asked to make payment arrangements or seek another physician. If those patients come back asking if we will care for a new pregnancy, we reserve the right to accept and refuse them.

I think one needs to be careful about ordering lab work if you do not intend to be the primary caregiver for the pregnancy. It would be easy for the patient to claim abandonment and coerce you into being her physician.

If you are not to be her physician, she must be referred to another MD or a program that CAN care for her pregnancy. We have such a group of Family physicians whose funding comes from state and local sources and they take on the majority of the indigent and near indigent pregnancies.

Optimally, our patients notify us that they are pregnant, we then schedule them for a formal New OB visit at which time unless a pregnancy loss is in progress or the patient expresses a desire for termination, we proceed with a full history, physical, and laboratory evaluation.

For 7 years, I have done the first panel at 16 weeks along with the state mandated afp test. (mandated to offer, that is...interestingly many patients think that the state mandates that they HAVE the afp test, shades of Big Brother!). This way, the "normal" patient gets poked twice. Once more at 28 weeks for the 1 hour glucola.

If additional tests are needed, such as toxo titers, CMV, anticardiolipin, etc., then I do the labs at the first visit.

Incidentally, I do a TVS on EVERY OB patient at the first visit, before I see them as a new consult. This has saved countless times where we sit and talk about pregnancy for 30 minutes only to immediately learn that the pregnancy is a missed Ab.

We get our prenatal profile at he first visit whenever in the pregnancy that is. with multiple practitioners it is they easiest way to keep tract of the testing. We also have a number of patients apply for WIC benefits and we need labs to fill out those papers.

We draw extra tubes of blood when we do a pregnancy test. Our lab has it set up that when the pregnancy test is positive they automatically do the rest of the prenatal profile so the patient only gets stuck the one time.

For new OB's, I schedule a first visit at 10 weeks with my nurse. At that visit, the above labs are drawn, patient and partner watch video on prenatal care, initial history performed with FHT's documented, vitamins started, U/S ordered if dates poor, orientation to practice performed with reading assignment, etc. These are done in a block on my half day off.

First MD visit scheduled at 12 weeks, labs reviewed, history reviewed, physical with cultures & Pap performed, prenatal visit.

I see potential liability in waiting to perform baseline tests weeks after you have formed caregiver relationship with patient.

I am concerned that if the initial bloods are delayed until 16-18 weeks hemoglobinopathy detection will be delayed. If women are African-American we get hgb electrophoresis early so that if she is AS or SC, there will be time to test the FOB, and do genetic referral if both have sickle trait. Early testing will allow identification of a woman with a low MCV so that she, also, may get hemoglobin electrophoresis in a timely fashion to diagnosis (or rule out) that trait.

I think that once the duty has been established, that the testing should be done. I have a fear that if the tests are not done immediately, there is the potential to lose the patient to follow-up.

I suppose that I need to describe my patient population. I care mainly for medicaid recipients and undocumented immigrants who occasionally for various reasons find it difficult to return to see me in a timely fashion. It is not uncommon to see a patient once as a referral from the hospital early in gestation and then not again until late pregnancy or labor. I loathe to ponder the consequences of a missed cervical cancer, alloimmunization (or preventable alloimmunization), severe anemia, thrombocytopenia, hemoglobinopathy, latent syphilis, chronic hepatitis B, AIDS, etc...

If the tests are done, at least there would be more of an effort to contact and follow-up on an abnormal finding.

We do all of the prenatal early testing at the first visit including Tay Sachs, CF, Hemoglobin electrophoresis, etc. Sometimes the Tay Sachs takes several weeks. On occasion we will do it on the second visit, but along with HIV testing, we feel the info is best known early.

The one benefit (other than early knowledge of the type and Rh) that I can think of is knowing rubella status early in pregnancy. If exposure occurs it could guide management significantly.